In recent years, there has been increased development in equipment and techniques for farming without tilling the entire surface of a planting field. Such farming is generally referred to as "no-till" farming. With no-till farming, the stubble from a crop from a preceeding growing season remains uncultivated during a subsequent planting and growing season. Seed for the new crop is simply planted through the stubble of the previous season's crop.
No-till farming techniques generally rely upon a disk type soil opener to break the surface of the soil in a localized area so that seed, fertilizer, and other agricultural chemicals can be placed directly into the soil. When disk type soil openers are used, it is necessary for the disk to penetrate into the soil to open a furrow into which the seed or other materials can be placed. Because the field has generally not been cultivated, there is usually straw or other stubble type debris on the ground surface. The disk soil openers must penetrate the debris for engaging the topsoil, and laterally directing the residue and soil away from the furrow being formed.
In no-till farming, it is desirable that all the rotting debris and residue be scraped clear of the furrow where seed is to be placed. No-till farming has suffered from difficulties caused by residue being tucked into the furrow by the soil opener. Residue tucked into the furrow can add to problems associated with various plant diseases such as pythium. In addition to disease, debris in the furrow also inhibits good seed germination and seeding emergence.
Residue and rotting debris can be beneficial when scraped clear of the furrow and localized adjacent thereto. The residue helps the soil to retain moisture adjacent the furrows. Additionally, the residue prevents exposure of the furrows to extreme temperatures and wind. Further, the concentration of residue material in rows adjacent the furrows results in the residue feeding upon itself creating more organic life and corresponding nutrients for the soil. Accordingly, residue can be extremely beneficial when properly manipulated within the seed zone.
It is also desirable that seed be placed within the soil at a predetermined depth. The desired depth varies with different seed varieties. Additionally, for a given seeding it is desirable that seed be placed at a uniform depth from the ground surface. Optimum crop yield can be significantly affected if seed placement depth varies as much as one inch. Seed placed at an even depth across a planting field assures that all plants germinate and emerge from the ground together. Two or more germination dates will retard late emerging seedlings and correspondingly reduce yields substantially.
The prior art includes an apparatus referred to as a "duff scuffer" for scraping residue away from a line where seed will be placed. The duff scuffer is a fixed, conical disk angled from the direction of vehicle travel which is slid along the ground in front of the soil openers. Duff scuffers can be positioned to be very aggressive in removing residue and soil in the seed zone if desired. However, duff scuffers suffer from severe limitations. For example, duff scuffers can only be used with rows having a spacing for which they were designed, such as the common 15 inch spacing. Further, duff scuffers remove varying amounts of residue and soil as they travel over varying sloped terrain. This results in too little or too much material being removed as terrain varies. Accordingly, the depth of a furrow created can vary significantly causing seed to be placed at different depths across the field.
Another prior art device similar to the duff scuffer, referred to as a "residue reliever", was designed to remove debris from narrowly spaced seed rows. The residue reliever was a straight disc which was also angled from the direction of vehicle travel to move straw and other debris away from the seed row. Two residue relievers could be mounted to each tool bar of a seeding machine for removing debris from the narrowly spaced rows being formed. The residue relievers were mounted to the tool bar such that all debris was caused to flow in one lateral direction relative to the direction of seeding machine travel. Residue relievers had drawbacks similar to those of the duff scuffer, such as removing varying amounts of residue and soil as they are caused to travel over various slope terrain. Additionally, at higher travel speeds the residue relievers caused debris scraped from one row to be forced into an adjacent row causing debris to be imbedded therein. Further, the scraping of material into one lateral direction necessitated that the seeding machine be operated in only one direction around a planting field to prevent debris being scraped in a given path of travel from flowing into a previously created path.
Accordingly, a need remains for a device which more effectively scrapes residue from the front of seed openers and concentrates the residue in rows adjacent furrows.